Terminology Tuesday: Transubstantiation
The theory of the Eucharist officially taught by the Roman Catholic Church. According to this view, during Communion the substance or essence of the bread and wine is miraculously transformed into the body and blood of Christ, even though the accidents (outward appearances) of the bread and wine remain the same.
Evans, C. Stephen, Pocket Dictionary of Apologetics & Philosophy of Religion (Downers Grove, IL: InterVarsity Press, 2002).